Banished forever NS
12 May 2001Puny planets like our's get flung into deep space by their
big brothers

So what's the score?
NS 12 May 2001 Humans may have thousands more genes than
the genome sequencers have led us to believe

Mungo Echoes NS
31 Mar 2001

A MAN who died about 60,000 years ago in Australia may be about
to turn our theory of human origins on its head. Researchers in
Australia have accomplished the extremely difficult feat of extracting
DNA from his skeleton, and were astonished to find that it looks
like nothing they have ever seen before. The DNA, which is the
oldest ever recovered from human remains, shows that while the
man is completely anatomically modem, he came from a genetic lineage
that is now extinct. This finding challenges the prevailing theory
that all modern humans are descended from a group of people who
migrated from Africa around 100,000 years ago. "It's remarkable-totally
unpredicted, says anthropologist Alan Mann of the University of
Pennsylvania. "What it says is that the more we know [about
human origins], the more confusing the picture becomes."
Mungo Man's remains were found on the shores of Lake Mungo in
south-eastern Australia in 1974. They were originally radiocarbon-dated
to about 30,000 years old, but in 1999 a reassessment using three
different techniques showed the bones to date from around 60,000
years ago. In 1995, a team led by anthropologist Alan Thorne of
the Australian National University in Canberra began an attempt
to extract genetic material from the remains. Doctoral student
Gregory Adcock and his colleagues at CSIRO Plant Industry managed
to replicate and sequence a single gene from Mungo Man's mitochondria,
the powerhouses of cells whose small genome is passed down the
female line. Simon Easteal, an evolutionary geneticist at ANU,
then set about analysing the sequence and comparing it with sequences
of the same gene from nine other early Australians-ranging in
age from 8000 to 15,000 years-as well as 3453 contemporary people
from around the world, chimpanzees, bonobos (pygmy chimps) and
two European Neanderthals. Easteal looked for patterns of descent
and worked out which "genetic tree" fitted the data
best. According to this evolutionary tree, chimps and bonobos
were first to branch off the trunk leading to modern people. Neanderthals
split off next, then Mungo Man's line and finally the line that
led to the most recent common ancestor of contemporary people,
including the ancient Australians but excluding Mungo Man. "We
can say with a high degree of confidence that modern people arrived
in Australia before the new lineage [of the most recent common
ancestor] arrived," Easteal says. According to Thorne, the
findings-due to be published next week in the online edition of
the Proceedings of the National Academy of Sciences-threaten to
topple the leading theory of human origins, the "outof-Africa"
model. This proposes that all living people are descended from
a group of modern Homo sapiens who left Africa roughly 100,000
to 150,000 years ago. Their descendants spread around the world,
replacing existing populations of "archaic" people,
such as Neanderthals and the more ancient Homo erectus. But if
anatomically modem humansfrom a lineage that emerged before the
most recent common ancestor of people todaywere living in Australia
60,000 years ago, "a simplistic out-of-Africa model is no
longer tenable", says Thome Thorne is one of the founders
of the rival "regional continuity" model, which postulates
that H. erectus began migrating from Africa over 1.5 million years
ago, and from these migrants H. sapiens evolved at the same time
in various regions around the world. Those early people remained
on the same evolutionary path by sharing their genes through interbreeding.
In Thorne's scenario, Mungo Man's ancestors probably evolved in
Asia. They gradually migrated to Australia, where the lineage
vanished. Because the lineage is based on a single mitochondrial
gene, it is too early to know exactly what happened. The clan
could have been wiped out by newcomers, or the gene may, for some
reason, not have been passed from mother to daughter. That is
why out-of-Africa proponents, including ANU physical anthropologist
Colin Groves, argue that the new data does not knock their model
from the top of the theoretical pile. The genetic evidence is
equivocal, he says. "The African-origin model stands or falls
by the fossil evidence. In my opinion, it stands." But Groves
praises Adcock's technical achievement. Retrieving such old DNA
is a "real coup", he says. Leigh Dayton, Sydney

Black Silicon NS 31 Mar 2001

Recently the use of fast pulsed lazers against a silicon wafer
in he presence of sulfur hexafluoride has been shown to induce
a black surface containing the crystal skeleton etched by fluorine
to which sulfur atoms have attached broadening the conduction
band so that from the infra-red through the visible, there is
up to 97% absorbtion. This is expected to produce up to a doubling
of efficiency of silicon solar electric panels and super sensitive
video cameras and instruments.

Scrub the planet clean NS 31 Mar 2001

Giant chemical ponds could suck up as much C02 as we produce

IF FORESTS are not sucking up enough carbon dioxide to halt
global warming, why not make an artificial "superforest"
instead? A team of US government researchers estimate that a superforest
which covers 200,000 square kilometres-roughly the size of Minnesota-would
absorb CO, as fast as humanity is now churning it out. Most strategies
to curb global warming focus on producing less CO,. But Hans Ziock
of Los Alamos National Laboratory in New Mexico argues that we
need to concentrate more on removing CO, with "scrubbers".
Carbon dioxide scrubbers were first suggested as a way of reducing
emissions from individual power plants and even vehicles. But
installing them would be a huge burden on existing industries.
Now Ziock and colleagues Klaus Lackner and Scott Eliott say you
don't actually have to build the scrubbers where the CO, is produced.
Lackner studied a simple reaction in which a calcium hydroxide
solution absorbs dilute CO, from the air. You can then recover
the solid calcium carbonate from the scrubber and heat it to extract
the CO,. The calcium oxide residue is recycled back into the solution
and the pure CO, is reacted with naturally occurring magnesium
silicates to form a stable rock-like solid that's easy to dispose
of. Ziock reatised that the wind would play a crucial role. "Once
every week the wind goes all the way round the Earth, so one can
process a large fraction of the atmosphere over the course of
a few years." In the lab, the researchers tested how much
CO, would be absorbed by a static scrubber with typical winds
flowing over it. Based on this data, they estimate that a huge
scrubber, essentially a collection of calcium hydroxide ponds
with an area of 200,000 square kilometres would remove about 7
gigatonnes of C02 per year-equal to the amount people produce.

The team also calculated that the forest could be a fraction
of that size if you draw up more solution and expose more of it
to the air using vertical fences with branching features, like
windmills or trees. Such str-uctures would be able to absorb 20
to 30 times as much CO, as a regular forest.

Other researchers say the idea compares favourably with other
ways of reducing emissions, such as converting electricity production
to wind or solar power. "I'm really happy to see some new
and clever thinking, " says Jae Edmonds of Pacific Northwest
National Laboratory's office in Washington DC. The cost is a worry,
says F. Sherwood Rowland of the University of California at Irvine,
but "the longer the population keeps releasing CO, directly
to the atmosphere, the more likely the answer will require driving
levels back down." Eugenie Samuel

More at: Geophysical Research Letters (vol 28, p 1235)

Protests take
the shine off golden rice NS 31 Mar 2001

CONTROVERSY continues to surround the development of genetically
engineered "golden rice" designed to combat vitamin
A deficiency.

After talks with Greenpeace at the headquarters of the International
Rice Research Institute in the Philippines last week, IRRI researchers
said it would be at least four years before field trials would
start. But the Peasant Movement of the Philippines (KMP), a radical
group which campaigns against the globalisation of food production
and

GM crops, still plans to demonstrate against IRRI next week.

Golden rice is engineered to contain beta-carotene, a precursor
of vitamin A. Shortage of the vitamin in food is thought to kill
up to 2 million people a year worldwide. IRRI, a publicly funded
research body responsible for the creation of high-yield rice
varieties, took delivery of samples of golden rice in January,
after several companies, including Syngenta Seeds and Monsanto,
handed over the rights to its development.

But last week, IRRI played down the seed's potential. "Much
work remains to be done to develop golden rice into the successful
strategy we feel it can become to help combat vitamin A deficiency,"
says IRRI director Ronald Cantrell. At the moment, the crop contains
only low level,s of beta-carotene, he says. "It will be at
least three to four years before there are any field trials and
another two years before it may reach farmers."

Greenpeace has said that researchers have failed to look for
natural rice varieties that could be interbred with modern strains
to provide vitamin A. And it accused the biotech industry of 'using
the misery of mothers and children" to gain acceptance for
GM crops. But after the meeting, Greenpeace's South-East Asian
campaign director Von Hernandez praised IRRI's 'more honest"
assessment of the potential of golden rice.

The KMP's leader, Rafael Mariano, says the Philippines' rice
industry is In crisis after the liberalisation of trade. 'Golden
rice can only make matters worse," he claims. Fred Pearce

Gofta catch them all NS 31 Mar 2001

Europe wants a licence to kill off one of the world's last
great fisheries

THE European Union is demanding an increase of up to 60 per
cent in the amount of fish its trawlers are allowed to catch off
West Africa. Conservation scientists are appalled by the proposals.
They say these waters are already seriously overfished, and that
such large catches will be unsustainable.

The demand comes as the EU is proposing to drastically cut
its fishing fleet to save dwindling fish stocks in the North Sea.
Nutrient-rich cold water rises to the surface along 2000 kilometres
of the Atlantic coAst from Morocco to Guinea-Bissau, making this
one of the world last great fisheries. But since the arrival of
foreign trawlers, particularly from the EU, in the past decade,
fish stocks have crashed.

"It is clear there is overfishing throughout the region,"
says Pierre Campredon, a French marine biologist who advises the
Mauritanian government on fisheries. 'And there is huge wastage.
Shrimp trawlers often throw back more unwanted fish than they
catch.' Several hundred trawlers from Spain, the Netherlands,
Portugal and other EU nations operate in the zone under licences
negotiated between the EU and West African govemments. The three
largest licences, covering waters controlled by Mauritania, Senegal
and Guinea-Bissau, are up for renewal this year.

Europe is pushing for big increases. In the first negotiations
of the year, which continued in Dakar this week, EU negotiators
have asked Senegal for a 61 per cent increase in licensed catch
from the end of April, according to Senegalese negotiators.

Senegal's fish stocks are 'at a critical moment" says
Amadou Wade of Fenagie Peche, the country's fisheries federation.
'There is pillage, both by Senegalese and foreign boats."
Foreign trawlers, dominated by the EU, take 100,000 tonnes of
fish from Senegalese waters each year, Wade says. The negotiations
with Senegal are likely to set a precedent for talks in the coming
weeks with its neighbour Mauritania, which has the richest fishing
grounds in the region.

West African governments feel under pressure to oblige the
EU, says Campredon. 'These countries have large debts. They say
they cannot refuse the EU for that reason." Wade, one of
Sengal's negotiators, says that "the EU could refuse to let
us have access to its markets for trade if we don't comply'. .
The revelations come at an embarrassing time for the EU, which
has a policy of supporting sustainable fisheries. Last week, the
European Commission announced plans to cut the EU fleet by 40
per cent and radically overhaul its fisheries policy, including
its negotiations with foreign governments. Otherwise, it warned,
'the status of the Community as a responsible international player
will be undermined".

EU fisheries spokesman Gregor Kreuzhuber this week refused
to discuss the detail of the negotiations. "The Commission
hasn't formally mentioned figures," he said. 'Any final agreement
will be subject to an assessment of the resources." Fred
Pearce, Dakar

The first split second Govert
Schilling NS 30 Mar 2001

During inflation pwerful gravitational waves should have been
wrenched into existence. Just tlike the density fluctuations that
got blown up into galaxy seeds, other kinds of wrinkles in space-time
were inflated into travelling waves.

Gravitational waves would have passed unaffected through the
primal fireball so they would be carrying a signal from the dawn
of time. Some peculiar instruments are being built to detect these
but we are more likely to detect them from their foot prints faint
marks on the surface of the primordial fireball.

When the atoms of hydrogen first formed the photons which had
been bouncing in the plasma headed off into space stretched from
a brilliant hot gas by the expansion of the universe all

that's left is a very faint microwave glow known as the cosmic
microwave background (CMB). This primordial radiation was discovered
in 1965.

There are tiny differences in the brightness or temperature
of the CMB between different parts of the sky. These were seen
by NASA!s Cosmic Background Explorer satellite (COBE) in the early
1990s, and have been studied in much more detail by balloon experiments
like Boomerang and MAXIMA (Ne,w Scientist, 16 December 2000, p
26).

Some of this variation traces the slight density fluctuations
in the early Universe, and some of it comes from Doppler shifts
produced by moving gas. Giant sound waves propagated through the
blazing hot matter, compressing and diluting it, and as gravitational
waves warp whatever they pass though, they must also have squeezed
and stretched the primeval fireball. Unfortunately, no matter
how accurate the measurements of brightness, cosmologists will
never be able to tell one contribution from another, so it's not
possible to separate the effect of primordial, inflationary gravitational
waves from the real density enhancements or from the effect of
sound waves.

Luckily there is a subtler message in the microwaves: polarisation.
Each microwave photon vibrates in a particular directionits plane
of polarisation. Usually, each photon is polarised in a different,
random direction, but when ionised matter is moving it imposes
an overall direction of polarisation on the radiation it scatters.

And crucially, gravitational waves generate a distinctive type
of polarisation, unlike the patterns made by density changes and
sound waves. If you measure the polarisation direction for every
part of the sky, and draw a short line in that direction at each
particular spot, what you get looks a bit like a map of wind velocities
on Earth. Gravitational waves create swirl-like patterns, unlike
any other phenomenon. To see these patterns, what we need is the
microwave equivalent of Polaroid sunglasses. A set of parallel
wires will stop waves with one polarisation while letting others
pass. By rotating this set-up and measuring how much radiation
leaks through, you can work out the polarisation. caught the thief?
Not yet. The will probably be very weak, so highly accurate measurements
ightness of the background to iable signal. ew balloon-borne and
ground based instruments stand a chance. At the South Pole, DASI
(Degree Angular Scale Interferometer) combines signals from 13
telescopes, making it a sensitive and high-resolution instrument.
John Carlstrom, an astrophysicist at the University of Chicago,
thinks it might be the first to catch CMB polarisation. Meanwhile,
Fred Lo of the Academia Sinica in Taipei, Taiwan, is in charge
of AMIBA (Array for Microwave Background Anisotropy), a large,
sensitive 19-element interferometer due to be built in 2004, either
at Mauna Kea, Hawaii, or in Chile. And two balloon-borne experiments
that hit the headlines last year with their detailed measurements
of the microwave background will fly again later this year: MAXIMA
this spring, and Boomerang in December. Jeff Peterson of Carnegie
Mellon University in Pittsburgh, Pennsylvania, expects one of
these instruments to detect CMB polarisation within the next three
years. And the highly sensitive European Planck satellite, which
will be launched in 2007, will almost certainly see it. Because
gravitational waves contribute only a small part of the total
polarisation, even Planck probably won't be able to extract the
gravitational inflationary signal. "I'd bet my money on post-Planck
missions," says Robert Caldwell of Dartmouth College in Hanover,
New Hampshire. It will probably be another decade or so before
the weak polarisation signal from primordial gravitational waves
can be tracked down. So the challenges are great. But then, the
stakes are high. From the polarisation data, it should be possible
to deduce the strength of the gravitational waves. This, in turn,
tells you when inflation took place. The earlier inflation started
off, the more violent the expansion, and so the stronger the gravitational
waves are expected to be.

And if we know when it happened, we might find out why. It
was once thought that inflation took place 10-31 to 10-31 seconds
from time zero, according to Caldwell, when an original cosmic
superforce split into three independent forces: the strong and
weak nuclear forces, and the electromagnetic force. This force
splitting happens when space goes through a phase transition,
like the transition from liquid water to ice. The energy released
by the phase transition is what drives inflation.

But there is no definitive theory of how the three forces come
to be unified only a slew of tentative 'grand unified theories".
So there's plenty of uncertainty as to when and why the forces
split in the early Universe. Some theories say there are extra,
hidden dimensions to space. If these extra dimensions are as large
as a fair fraction of a millimetre, inflation might have occurred
as late as 10-14 seconds after time zero. 'But,' says Caldwell,
'this is a rock bottom latest time."

Finding the gravitational wave spectrum would knock out many
of the dozens of inflation models thought up by creative theorists.
"Right now," says Bram Achterberg of Utrecht University
in the Netherlands, "no single model seems to be more plausible
than any other, but from the gravitational wave spectrum it would
be possible to disprove some of them."

So studying the gravitational wave spectrum would be a powerful
way of probing extremely high energies, and examining theories
that describe the true fundamental structure of matter. Physicists
may never be able to build accelerators powerful enough to reach
the high energies experienced at the start of the Universe, so
tracing inflation may be the only way to do it.

Then again, we might find a spectrum that can't be explained
by inflation at all. The theorists would have to start from scratch.
Nobody really knows what was going on in that first split second,
which is why a signal from the big bang would be so important.

It's not a sure thing, however. "If inflation took place
at a low energy scale, the gravitational wave signal will be too
small to be detected," says Peterson. This would not disprove
inflation, but it would extinguish any hope of looking beyond
the microwave background to the beginning of time.

GRAVITATIONAL waves from the beginning of time may be constantly
passing through the Earth, stretching and ftexing everything they
meet. But how can we detect them? A pair of huge devices called
UGO (Loser lnterforonieter Gravitational Wave Observatory) Is
being built In Louisiana and In Washington State. Each one will
use laser beams to monitor distances Inside two 4-kilometre-long
tunnels, which should vary when a gravity wave passes through.
LIGO is the star among the new generation of gravitational wave
detectors-but It's not sensitive to the very-low-frequency waves
that are expected to come from the big bang. Moreover, the amplitude
of these waves Is probably too small to be measured by LIGO, even
if It were sensitive to the frequency. The planned space-based
detector called LISA (Laser Interferometer Space Antenna), due
to be launched In 20IO, samples lower frequency waves, but it
too will probably not be sensitive enough to pick up the feeble
prlrnordial waves.

Then agaln, although most theories do not predict high-frequency,
short wavelength gravitational waves, very little Is really known
about what happened less than a quadrillionth of a quadrillionth
of a second after time zero. There's at least one model, by Massimo
Giovannini of Tufts University in Medfbrd, Massachusetts, that
has large amounts of gravitational waves with frequencies of many
gigahertz coming from an earlier expansion phase, after lnflation.
At the University of Birmingham, Mike Cruise has a prototype detector
for these high ency waves. A gravitational wave can induce a tiny
rotation of the plane in which an electromagnetic wave moves.
SO Cruise and his colleagues are pumping microwaves around a circular
copper wave guide to try to amplify this effect to measurable
proportions. 'It's still many orders of magnitude less sensitlve
than what we ultimately need,' he says, 'but in the next couple
of years, we hope to make real technical progress.

Govert Schitiing is a science writer based in Utrecht, the
Netherlands

Further reading: The Inflationary Universe: The Quest for a
New Theory of Cosmic Origins by Alan H. Guth (Helix Books, 1998)
Catch the wave

Just a Youngster NS 13 Jan 2001

EARTH is probably a youngster among planets of its kind, says
an astronomer in Australia. This may mean that any intelligent
beings that have evolved on other Earth-like planets will be so
highly advanced that to them we seem little better than bacteria.
No wonder they haven't been in touch yet. Charles Lineweaver of
the University of New South Wales in Sydney says that Earth-like
planets orbiting other stars will be on average about 1.8 bilhon
years older than Earth. He deduced this figure by cleverly combining
a host of factors that determine the formatim and destruction
of terrestrial planets. One such factor is the way in which heavy
atoms such as iron have become more plentiful since the big bang.
The early Universe contained only the lightweight elements hydrogen
and hehum. All other atoms were made in the thermonuclear fumaces
of stars, and elements heavier than iron are only released into
interstellar space when old, massive stars explode as supemovas.
Rocky planets cannot form around a star unless there are enough
heavy atoms in the dust it is made of, so there were none when
the Universe was young. However, a brew too rich in heavy elements
would lead to "hot jupiters"@ant planets orbiting so
close to their parent stars that they destroy newbom earths. a
paper submitted to the journal Icarus, Lineweaver concludes that
three-quarters of all Earth-hke planets must have been around
longer than the Earth and that the average age is 6.4 bilhon years,
compared with Earth's 4.6 billion years. "This analysis gives
us an age distribution for hfe on such planets and a rare clue
about how we compare to other hfe which may inhabit the Universe,"
he says. But neither Lineweaver nor anyone else will commit themselves
on what this tells us about the prospects of finding ETs. "The
odds against simple life are still completely uncertain,"
says Martin Rees of the University of Cambridge. "We don't
know the chance of any extraterrestrial intelligence evolving
anywhere, nor what variety of evolutionary tracks are possible."
However, Lineweaver's calculations could offer a hint about why
we haven't picked up any radio signals from alien beings. Intelligent
life on older planets may have advanced as far beyond us as we
are beyond bacteria, and such beings would be unlikely to communicate
via a medium as primitive as radio waves. "Certainly this
can be a way of explaining the 'Great Silence'," says ET
hunter Paul Schuch, executive director of the SETI League in New
Jersey. "But I rather think our lack of success is more related
to the fact that, on the cosmic clock, we just started looking
yesterday. These things take time, and require great patience."
Marcus Chown

More at: xxx.lani.gov (Astrophysics e-print 0012399)

Just when you thought it was safe to stop evolving, culture
and technology may be itching to wipe out your genes. Is human
evolution about to take off, asks Philip Cohen

The Future of Human Evolution
NS 13 Jan 2001

IT'S THE ultimate problem in family etiquette. The researchers
from your local lab phone to say they've thawed out a 50,000-year-old
ancestor of yours, and they want to bring him over. The question
is, should you welcome this forebear into your home? Perhaps,
like palaeobiologist Simon Conway Morris of Cambridge University,
you believe that we differ very little from people who lived tens
of millennia before us. He suggests that, given suitable education,
your long-lost kin would have no problem holding their own in
your business or at your local bistro. "They could walk into
the room and, given a haircut, they'd fit right in," says
Conway Morris. In other words, our evolution has been all but
over for quite some time. There is a certain comfort in that thought.
After all, if you decide to go for cryogenic preservation when
you die, it could be you who's cast in the role of the defrosted
dinner guest. But before you make those hotel reservations for
a family reunion in 50,000 years' time, you should be wamed that
there are those who strongly disagree with Conway Morris's forecast
for our species. Far from slowing evolution down, they say, technology
and culture could be accelerating it to a furious pace. So instead
of being welcomed as an equal, you could be shunned as a primitive
freak. Despite their varying visions of our future, scientists
on all sides of the debate over our evolutionary destiny agree
about how things started out. In the beginning, all life on Earth
was at the mercy of the same evolutionary forces of natural selection.
Competition, starvation, predators, disease and sometimes bad
luck took their toll on our ancestors and thereby pushed and pulled
the gene pool in different directions. Overall, those with genes
that suited the environment survived and reproduced, while those
with an inappropriate genetic constitution disappeared into oblivion.
Then, about 5 million years ago, primate evolution split along
two tracks: one leading towards humans, the other towards chimpanzees.
A million years later, our ancestors adopted an upright gait,
and 2 million years after that their bodies and brains began to
grow and they started making primitive stone tools. The first
modem-looking humans appear in the fossil record about 130,000
years ago. By 50,000 years ago, there is evidence for folks who
appear to have distinctly modem bodies and lifestyles. They created
complex tools and jewellery, built shelters, buried their dead
in graves and probably had the language skills to chat about what
they were doing. And through these simple acts, the newly minted
Homo sapiens unintentionally thwarted the very forces that had
created our species, says Conway Morris. Effective weapons removed
most of the threat of predators, and agricultural development
beat back starvation. "The technological innovations that
took place during this period were astounding," he says.
'But there is no sign that this was due to genetic changes."
And while we still haven't banished human hunger or disease from
the planet, the trend is clear. We are cushioning ourselves from
the forces that shaped our biology for aeons. Steve Jones, a geneticist
at University College London and author of The Language of Genes,
agrees. Culture and technology, he says, spelled the beginning
of the end for evolution in its classic sense-natural selecfion
of genes better suited to their environment. In the developed
world, child mortality has declined drastically and family size
tends to be small. Put simply, natural selection doesn't take
place if everyone, regardless of the genes they carry, has two
children who survive to reproduce.

Too much alike

And this is only half the story, Jones adds. For evolution
to proceed, there must not only be environmental rigours that
weed out the weakest, there must also be genetic variation between
members of the population so that some are better suited to cope
than others. Humans, it turns out, are already remarkably similar
at the genetic level. There is only about a 0.1 per cent difference
between your DNA and that of any passerby hi contrast, among our
close relatives the chimpanzees, the variafion is at least five
times that. Jones believes that modem life continues to chip away
at the few remaining differences. For instance, mutations in the
chromosomes of eggs or sperm become more common as parents age,
but this source of genetic variation is disappearing because parental
age is decreasing as couples tend to stop at two kids. What's
more, in the past, some human mutations were preserved because
they provided protection from disease. But as public health measures
eliminate deaths from these diseases, the number of people who
carry the mutation decreases. All the while, says Jones, our knack
for buflding machines that whisk us around the planet dashes any
hope that@ we might spin off a new species of human. That's because
the spawning of new species requires reproducfive isolation, and
geographic barriers often provide just the right type of genetic
privacy. But our wanderlust regularly gives the gene pool a good,
homogenising stir. With mutational fuel running low and the engine
of natural selection idling, Jones concludes that our evolution
is, at most, coasting slowly to a standstill. But according to
Lynn Jorde, a human geneticist at the University of Utah, it is
just changing direction. Agricultural developments may have made
famine less frequent, he points out, but they have also caused
people to five in larger, more densely populated areas, increasing
the likelihood and impact of epidemics such as cholera and AIDS.
In addition, our frequent globetrotting has allowed disease organisms
to hitch rides into even the most remote corrununines. "All
this presented our immune systems with greater challenges,"
he says. Science may have spawned medicine, but it has also unleashed
an industrial and technological revolution that spews out radioactivity
and chemicals that can contribute to an increase in our mutation
rate-or act directly as selective forces. "A thousand people
a day die of cigarette smoking in the US alone," says Jorde.
"That's got to have some impact." Even a little impact,
genetically speaking, could go a long way. Remember that the vast
difference between us and chimps comes down to a mere 1.5 per
cent difference in our DNA. In fact, our current genetic variability
is still high enough to pose a significant medical problem. Genetic
factors mean that new drugs often prove ineffective on a significant
chunk of the population (New Scientist, 4 November 2000, p 31).
Still, we may ultimately manage to thwart the health and pollution
problems of our own making. So would that lead to human evolution's
last breath? Christopher Wills of the University of Cahfomia in
San Diego certainly doesn't think so. He believes that as the
deadly blows of past selective pressures disappeared, we began
to be shaped by more subtle but equally persuasive forces. "It
is less obvious. But you don't have to pile up bodies in the street
to have evolution." In fact, he believes that rather than
slowing us down, our culture has probably propelled us into developing
at unprecedented speeds. Culture itself shapes our genes. In those
societies where milk drinking is an ancient pracfice, for example,
people have genes that allow them to digest the milk sugar lactose.
People whose ancestors were not milk-drinkers tend to lack these
mutations. Wills argues that today's globalisation increases the
potential diversity of the human gene pool by bringing together
such specialised versions of genes that had been separated through
much of history. "This creates new combinations that may
never have been seen before," he says. In his book Children
of Prometheus, Wills argues that the major evolutionary influence
of culture is to create new environments and select for human
generic diversity. Fine motor skills, for instance, were probably
not much use when our ancestors were doing little more technical
than smashing rocks. But in a more modern society you can benefit
from both big muscles, and the delicate manipulations of a watchmaker.
One talent of the human animal is to devise ever more exacting
mental and physical challenges. Wills cites the recent rise in
popularity of extreme sports. "These people are now succeeding
based on skills that didn't exist even a few years ago,"
he says. He also points out that diversity itself can be selected
for. Outside our species, for example, researchers have found
that trees that are rare in forests reproduce more often than
more common varieties. The thinking is that a sparse population
gives species-specific parasites less of a chance to breed. Similarly,
he argues that tare traits are rewarded in our culture. Musical
geniuses thrive exactly because they are exceptional. If we all
had perfect pitch and virtuosity, we would clearly be less impressed.
It is in intellectual and psychological areas that our culture
generates the greatest advancement and diversity, according to
Wills. The decision not to have children, for example, has exactly
the same evolutionary impact as losing a child through predation
or disease. Now consider that this form of selection might be
triggered by our genetic constitution. Wills points out that people
who cope badly with stress in their lives often choose not to
have children, so the effect may be a bloodless coup where those
genes that allow us to deal with the stresses of modem life emerge
victorious. Jorde agrees that the evolution of the brain is a
neglected area. "The best new estimates say a third or more
of our genes play a role in the development or function of our
brain. We're only just beginning to understand what that means
for our evolution," he says. The dystrophin muscle gene,
for example, which causes muscular dystrophy wheh faulty, is also
expressed in the brain. So too are XRCC4 and Lig IV, which are
involved in immunity. As a result, genetic changes that have improved
muscle tone or our ability to fight disease could have had psychological
or intellectual repercussions.

All this suggests that it would take a lot more than a haircut
to bring our primitive ancestors up to scratch. They may have
been mentally incapable oi dealing with modem society. But it
isn't always obvious how to chart the effects of culture on evolution.
Do increases in the use of birth control select for better parents,
because only those that really want children tend to have them?
Or does it mean that a great many more children are bom to parents
who mess up their use of pills or condoms, selecfing for parents
who are less than careful? Richard Dawkins of Oxford University
questions whether a good case can be made for close co-evolution
of human genes and culture. He points out that much cultural change
is simply too fast and too fickle. It takes a reproductive generation,
say 25 years, for a slight change in the human gene pool to emerge,
while fashions change almost daily. Dawkins says that if the human
gene pool were a cork thrown into the ocean, then most cultural
effects would be like chaofic winds tossing it back and forth,
without tugging it in any particular direction. Yet, continuing
the metaphor, Dawkins admits there might be what he calls "Guff
Stream effects"-long-term trends within society that draw
our species in a particular direction. One of his nominees for
such a deep cultural current is the growth of computational power.
The density of transistors on computer chips has doubled on average
every 18 months since the integrated circuit was invented, a phenomenon
known as Moore's law. Of course, this would influence human evolution
only if the ability to cope with this electronic explosion provides
some reproductive advantage. Is that so crazy? The Intemet has
spawned a whole generation whose social interaction is increasingly
electronic. Chances are that some readers of this feature will
know couples who forged e-relationships that have blossomed into
e-marriages. And technology's influence on mating choice extends
beyond the Intemet's great cyber-singles bar. Recently, researchers
from the University of Liverpool reported that young men in pubs
and bars use their mobile phones as lekking devices, meeting in
groups and displaying their technology as a symbol of status and
wealth, in much the same way that male grouse congregate and show
off to attract mates (Human Nature, vol 11, p 93). Whether or
not culture has shaped our biology in the past, John Campbell
of the University of California, Los Angeles, thinks we will soon
consciously control our own evolution. At a conference two years
ago called Engineering the Human Germline, which he helped organise,
most experts agreed that the first humans with designer genes
will probably be born in the next two decades (New Scientist,
3 October 1998, p 24). 'It will start in the areas that are least
controversial, such as treating genetic disease," says Campbell.
"But people will soon be dumbfounded by the possibilities."
For instance, certain fairly simple natural genetic mutations
are now thought to confer resistance to HIV or protection from
high diolesterol. And researchers are already hot on the trail
of genes that might enhance longevity and cognifive ability. Engineering
these refinements into human chromosomes would involve standard
genetic manipulations of single human cells and then using these
cells to create a clone-the same technology that made Dolly the
sheep possible.

The chosen people

Though no one has yet crossed the line and grown genetically
engineered human dones, the prospect seems closer flian ever.
Doily was a relatively new phenomenon two years ago, but now she
is just one of dozens of sheep, mice, coxvs, goats and pigs rolling
off the cloning production line. And only a few months ago, a
couple from Colorado caused an uproar by using genetic tests to
choose an embryo. They wanted a baby that would be a close tissue
match for their other daughter, who suffers from an inherited
blood disease. Some ethicists saw the episode as the slippery
slope towards fun-scale eugenics. If parents are already willing
to use genetic screening to create tissue donors, will it be long
before they begin to screen for babies with high IQ or superior
athletic ability? While many people recoil at the idea of "designer
babies", Campbell thinks that small groups are bound to use
the latest reproductive techniques to push the boundaries of human
evolution. "The technology is going to advance beyond what
our conservative society will embrace," he says. "But
I think we will see some people evolve at rates we haven't even
imagined yet." Geneticist Lee Silver of Princeton University
predicts a similar cottage industry of human evolution in his
book Remaking Eden. He speculates that cloning and other genetic
technologies could create a genetic elite, or what he dubs the
"GenRich" class, who would refuse to mate with "natural'
human beings and ultimately become a separate species. But Jones
doubts that even conscious effort could get us out of our evolutionary
rut. The GenRich would be hard pressed to keep their new genes
to themselves, he says. History shows that even in a highly stratified
society, the classes still mingle due to our basic, animal instincts.
"I believe in the healing power of lust," Jones says.
And a few improved genes among the 100,000 we possess, in a global
population of 6 billion, is a drop in the ocean. But even if Jones
is right and there is no way on Earth that a new humanoid species
could arise, engineer Robert Zubrin is betting it will anyway.
Zubrin, who is president of Pioneer Astronautics in Colorado,
thinks it will happen on another planet. He points out that the
very factors which Conway Morris and Jones believe have led to
a lull in human evolution-jet travel, light speed communication
and advanced medicine-have made it possible for us to venture
into space. "Some argue that this means we are at the end
of the history of humanity," says Zubrin. "But I think
that means we are at our first moments." Our destiny, says
Zubrin, is to leave the planet, just as our ancestors left Africa
and colonised the rest of the world. And our first stop could
be Mars, which might be made habitable through terraforming. In
fact, he believes that a fully functional Martian city with hundreds
of residents will be built in this century. And as surely as our
descendants shape that world, it will shape them. There would
be incredible selection for people whose genes help them survive
in the harsh environment, and even on a terraformed Mars this
would long persist. While providing Earthly childr@n with genetic
enhancements may seem like a frivolity, it would just be good
sense to endow Martian kids with the ability to endure a thinner
atmosphere and stronger solar radiation. And since the gravity
on Mars is only about one-third the strength of Earth's, Zubrin
suggests it might also be wise to give its inhabitants long, springy
legs to cover terrain more easily. The unprecedented geographic
isolation of this new civilisation and the speed of genetic selection
among its inhabitants would make it fertile ground on which a
new species could arise. While it might not be that surprising
that a rocket scientist such as Zubrin envisages a future in space,
some biologists are quick to agree with him. "If we find
even a distant planet that can support life, nothing will stop
us from getting there one way or another," says Wills. "That's
because our curiosity is orders of magnitude above that of other
species." . Perhaps that's why you can't help wondering what
you should bring for that family dinner party in the year 52,000.
It might be wise to hedge your bets. A good bottle of wine for
the parents, perhaps, and extremely long elastic trousers for
the kids.

Unleash the bugs of war NS 12 May 2001The US looks set to scupper talks on enforcing the bioweapons
treaty

THE Bush administration is on the brink of demolishing another
international armscontrol agreement. In Geneva this week, SO nations
are trying to finalise a mechanism for policing the 1972 treaty
banning biological weapons. The US is widely thought to have decided
to reject the protocol, which will collapse without its support.

But surprisingly, some arms control experts who support a stronger
bioweapons treaty say this could be a good thing. They argue that
the current proposal is so weak that it could help rather than
hinder would-be biowarriors. Others say the proposal must succeed,
because governments are unlikely ever to negotiate a stronger
one. Negotiations on the protocol began in 199S, after the exposure
of bioweapons programmes in Iraq and Russia made it clear the
Biological Weapons Convention needed teeth. The compromise proposal
on the table in Geneva this week calls on countries to declare
what biological defence facilities and high-containment laboratories
they possess, as well the agents they work with. A limited number
of random inspections of these facilities would then be made by
a proposed Organisation for the Prohibition of Biological Weapons,
to check the declarations. Stricter inspections could be made
if a government suspects it has been attacked, or that another
country has bioweapons-so long as other member states agree. The
US has been unenthusiastic about random visits ever since talks
began (New Scientist, 28 February 1998, p 16). Drugs companies
say they could endanger commercial secrets. The US delegation
in Geneva this week has said only that it is waiting for the Bush
administration to decide its policy.

But arms-control experts say the Bush team has already decided
to reject the protocol. "There are indications that it would
prefer that the concept either be radically reshaped, or simply
allowed to wither away," writes,james Leonard, former US
ambassador to the UN Conference on Disarmament, in this month's
Artns Control Today. "The new administration will almost
certainly reject the current proposal," says Alan Zelicoff
of Sandia National Laboratories in New Mexico, a US negotiator
until 1999. "And the

Senate is unlikely to approve it in any case.' But they and
others attribute this not to the current administration's distaste
for arms control, but to the proposal's weakness. For example,
states bent on cheating could simply not declare labs, or they
could grow pathogens in breweries (which need not be declared)
or antibiotics factories (which are exempt from visits). Countries
get two weeks' warning of random inspections, can limit what the
visitors see, censor their report and ban biological sampling.

Even following accusations of breaches of the treaty, the accused
still gets 108 hours' notice of an inspection-more than enough
to move or conceal cultures and equipment. Countries can also
deny access to facilities and prohibit sampling. In a report released
in Geneva this week by the Stimson Center, an arms-control think
tank in Washington DC, a panel of American scientists and arms
inspectors conclude that more research into how to carry out inspections
is needed. In a test organised by the Stimson Center last july,
two prominent infectious-disease experts, both veterans of bioweapons
inspections in Iraq and Russia, visited a high-containment laboratory
in New York state. The centre had secretly planted fake anthrax
cultures and records, and told the chief technician to "act
nervous". The team missed the "anthrax"-but did
find several spurious causes for concem.

Critics say this shows the proposed protocol could create unwarranted
suspicion instead of greater trust-alienating participants while
failing to catch culprits. "An impotent monitoring protocol
will implode sooner or later," the Stimson report concludes,
which means the bioweapons treaty could be "Violated at will
and possibly with impunity".

The question is what will happen if, as seems likely, the US
rejects the current proposal. Developing countries and Russia
will not sign unless the US does. Europe, which supports the protocol,
could try to prolong the current negotiations while trying to
bring the US back in. But the US could instead seek to have the
talks restarted from scratch, in an attempt to get a different
kind of protocol.

Oliver Meier of Vertic, a think tank in London, says that would
be the worst outcome. "The current proposal is weak, but
if it is made flexible enough, it can evolve. In the current political
climate we are unlikely to get a mandate to discuss a stronger
agreement. And we can't wait another six years."

The agonising choice now is between a treaty that will do little
to stop biowarriors, or nothing at all. Debora MacKenzie

Banished forever NS 12 May 2001Puny planets like our's get flung into deep space by their
big brothers

GIANT planets in faraway solar systems are .marching in towards
their parent stars, and banishing small planets like Earth into
outer space in the process. That's the conclusion of astronomers
in Canada who think they know why these giant planets end up so
close to their host stars. Around 60 extrasolar planets have been
discovered so far. Most are gas giants several times the size
of Jupiter and orbiting very close to their parent stars.

This has baffled astronomers because giant planets in our own
Solar System formed in the cold outer regions and have not shifted
inwards from their birthplace. Jupiter is about five times as
far away from the Sun as the Earth is, but in other solar systems
giant planets are sometimes closer to their star than Mercury.

One possibility was that the extrasolar giants also formed
in the outer regions of their systems, but lost energy and gravitated
towards their stars when loose gas rubbed against them. However,
this would leave them in small circular orbits. Instead, these
giants seem to have very elongated or .eccentric" orbits.

Now Norman Murray of Toronto University and his team say small
planets like Earth or Mars could explain the giants' close orbits.
They considered a system in which an outer giant planet completes
one orbit in the time it takes a closer small planet to orbit
twice. They found that the effect of the two planets periodically
lining up is enough to force other small planets in the system
into eccentric orbits.

Eventually the orbits of the small planets become so wild that
they either swing out into space forever or fall in towards the
star. At the same time, the giant planet soaks up extra angular
momentum and shifts into a tighter, more eccentric orbit. "This
mechanism is robust and can operate in real physical systems,"
says Eric Ford, who studies giant planet behaviour at Princeton
University in New Jersey.

A team led by Garik Israelian at the Astrophysics Institute
of the Canary Islands has found something similar happening in
a system with at least two extrasolar planets. The star's atmosphere
contains lithium-6, which is found in planets but only survives
in a star for a few million years (Nature, vol 41 1, p 163). This
suggests a giant planet sent its smaller companions careering
into the star relatively recently. "You don't want to be
around when that giant planet gets moving,' says Murray.

But why haven't the giant planets in our Solar System turfed
their weedy companions out into space? Murray suspects it's because
there aren't many small planets inside Jupiter's orbit, which
means the process would take a very long time-longer than the
time the Sun will take to blow up into a red giant near the end
of its life. "So I wouldn't worry about it," he says.

Eugenie Samuel, Boston More at: http://arXivorg/abs/astro-ph/0104475

So what's the score? NS 12 May
2001We humans may have thousands more genes than the genome sequencers
have led us to believe

"ONE giant leap for humility". "We're noth ing
special". "Scientists find only half as many genes as
expected". These are some of the headlines that appeared
after papers on the draft genome were published in February. Both
the public and private projects esti mated we had just 30,000
to 40,000 genes, far fewer than most previous figures sug gested-and
barely more than worms. But the low estimates have ignited a firestorm
of controversy. William Haseltine, head of biotech company Human
Genome Sciences (HGS) in Rockville, Maryland, has been the most
outspoken critic, attacking both the quality of the draft sequences
and the gene-finding efforts of those who com piled them. "They're
reading smudged text through foggy glasses," he recently
snarled. Hasettine claims to have found more than 90,000 genes,
while companies such as Affymetrix sell gene chips based on more
than 60,000 genes and DoubleTwist puts the number above 65,000.
But Craig Venter, head of Celera Genomics, the private rival to
the public genome con sortium, is standing by the lower estimate.

He calls it a "truth serum' for his competitors. So are
these companies wasting hundreds of millions of dollars on a wild
goose chase? Or could the public consortium and Celera end up
delaying the development of medical tests and treatments by denying
the existence of large numbers of genes? The accuracy of the draft
genome is not the issue. The controversy is about how you find
the fragmented parts of the genome that actually code for proteins.
There are 26,000 genes that researchers more or less agree on.
In the papers in Nature and Science (Ne,w Scientist, 17 February,
p 4), the public consortium and Celera estimated that there are
about another 10,000, based on computer programs that search raw
sequences for stretches that resemble known genes.

But the programs tend to throw up lots of genes that don't
really exist. To avoid counting these, Celera and the consortium
demanded evidence that gene candidates really are transcribed
to make the messenger RNAs that cells use to make proteins. "But
we only have transcription evidence for half the genes in the
body," admits geneticist Michael Zhang at Cold Spring Harbor
Laboratory in New York. That's where HGS and similar genome companies
come in. Instead of looking at the iaw sequence, they find genes
by combing thousands of different cells for bits of mRNA. These
are then turned into bits of DNA called expressed sequence tags,
or ESTS. Haseltine claims his ESTs provide evidence for more than
10,000 genes that aren't in the consortium's database. 'We have
made functional proteins, some of which we are developing as drugs,
that are not annotated as even existing in that text," he
says. But Celera and the consortium claim their estimates include
these proteins. Another problem with gene-finding programs is
that they can only look for code that resembles known genes. So
they not only turn up candidate genes that don't really exist,
they also miss lots of real genes. "Historically, gene-prediction
programs have tended to miss over 50 per cent of genes,"
says geneticist Michael Snyder of Yale University. A group at
Ohio State University in Columbus has analysed the same data that
the consortium looked at and estimates there are actually about
80,000 genes. In an as yet unpublishe paper, it claims that the
consortium's software has missed nearly 850,000 gene segments
for which there is protein or RNA evidence. While the debate should
be settled eventually, the uncertainty could have far-ranging
implications. Some fear that undiscovered genes-and thus potential
drug targetscould fall through the cracks. While many labs continue
to mine the genome for new genes, some are finding it difficult
to get funding. The head of one biomedical research lab, who preferred
not to be named, says his funders recently asked him why he was
continuing to look for genes when the "genome was finished".
"People should not give up the gene count," warns Haseltine.
Meanwhile, the rival parties are heading for a showdown. "There's
a simple way to settle the question," says Eric Lander of
the Whitehead Institute, one of the leaders of the consortium.
"Let's randomly select 3 per cent of the genome, have everyone
declare the genes that they believe to be in that region, and
test the proposed genes.' Let the games begin. Eli Kintisch, Washington
DC May 2001 o New Scientist www.newscientist.com